In typical CATV applications, a filter circuit or network is provided to pass signals having frequencies within one or more specified bandwidths, sometimes with a desired amount of signal attenuation, while blocking signals of other frequencies. It is convenient, but not necessary, to mount the electrical components such as capacitors, inductors, and resistors on one or more printed circuit boards in essentially conventional fashion. The circuit board carrying the filter circuit components is mounted within a suitable protective housing. Physical rigidity is required to maintain stable electrical response.
The greatest obstacle to achieving optimum circuit performance is often proper grounding. Each section of the electrical component or circuit board requires a connection to ground. When the ground contact is placed at one end of the board, the electrical path from the circuit sections to the ground contact lengthens as the section components are placed farther away from the housing ground contact. Inductance and resistance parasitics are introduced into the electrical path in proportion to its length, i.e., the longer the path between the circuit section and the ground contact, the greater the level of undesirable inductance and resistance which are introduced. The additional inductance limits the circuit operating frequency range while the resistance severely degrades the “Q” (quality factor) of the circuit.